github.com/cockroachdb/cockroach@v20.2.0-alpha.1+incompatible/pkg/sql/filter.go (about)

     1  // Copyright 2016 The Cockroach Authors.
     2  //
     3  // Use of this software is governed by the Business Source License
     4  // included in the file licenses/BSL.txt.
     5  //
     6  // As of the Change Date specified in that file, in accordance with
     7  // the Business Source License, use of this software will be governed
     8  // by the Apache License, Version 2.0, included in the file
     9  // licenses/APL.txt.
    10  
    11  package sql
    12  
    13  import (
    14  	"context"
    15  
    16  	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
    17  	"github.com/cockroachdb/cockroach/pkg/sql/types"
    18  )
    19  
    20  // filterNode implements a filtering stage. It is intended to be used
    21  // during plan optimizations in order to avoid instantiating a fully
    22  // blown selectTopNode/renderNode pair.
    23  type filterNode struct {
    24  	source      planDataSource
    25  	filter      tree.TypedExpr
    26  	ivarHelper  tree.IndexedVarHelper
    27  	reqOrdering ReqOrdering
    28  }
    29  
    30  // filterNode implements tree.IndexedVarContainer
    31  var _ tree.IndexedVarContainer = &filterNode{}
    32  
    33  // IndexedVarEval implements the tree.IndexedVarContainer interface.
    34  func (f *filterNode) IndexedVarEval(idx int, ctx *tree.EvalContext) (tree.Datum, error) {
    35  	return f.source.plan.Values()[idx].Eval(ctx)
    36  }
    37  
    38  // IndexedVarResolvedType implements the tree.IndexedVarContainer interface.
    39  func (f *filterNode) IndexedVarResolvedType(idx int) *types.T {
    40  	return f.source.columns[idx].Typ
    41  }
    42  
    43  // IndexedVarNodeFormatter implements the tree.IndexedVarContainer interface.
    44  func (f *filterNode) IndexedVarNodeFormatter(idx int) tree.NodeFormatter {
    45  	return f.source.columns.NodeFormatter(idx)
    46  }
    47  
    48  func (f *filterNode) startExec(runParams) error {
    49  	return nil
    50  }
    51  
    52  // Next implements the planNode interface.
    53  func (f *filterNode) Next(params runParams) (bool, error) {
    54  	panic("filterNode cannot be run in local mode")
    55  }
    56  
    57  func (f *filterNode) Values() tree.Datums {
    58  	panic("filterNode cannot be run in local mode")
    59  }
    60  
    61  func (f *filterNode) Close(ctx context.Context) { f.source.plan.Close(ctx) }
    62  
    63  func isFilterTrue(expr tree.TypedExpr) bool {
    64  	return expr == nil || expr == tree.DBoolTrue
    65  }